/Engine/Source/Runtime/MediaAssets/Public/MediaPlayer.h
Listen to EMediaEvent::MetadataChanged to catch updates to this data
Map with arrays of FMediaMetaDataItem entries describing any metadata found in the current stream
[TMap](API\Runtime\Core\Containers\TMap)< [FString](API\Runtime\Core\Containers\FString), [FMediaMetadataItemsBPT](API\Runtime\MediaAssets\FMediaMetadataItemsBPT) > GetMediaMetadataItems() const